Calipers.



No. 69|,682. Patented Ian. 2|, I902.

1F; WEIMAR.

GALIPERS. (Applicatibn filed m 2, 1901.

(No Model.)

UNITED STATES PATENT OFFICE.-

FRED WEIMAR, OF CHICAGO, ILLINOIS, ASSIGNOR OF TWO -TI'IIRDS TO T. D.HEWITT, OF FREEPORT, ILLINOIS, AND S. A. FRENCH, OF CHICAGO,

ILLINOIS.

CALIPERS.

SPECIFICATION forming part of Letters Patent No. 691,682, dated January21, 1902.

Application filed May 2,1901. Serial No. 58,436. (No model.)

To all whom, it may concern.-

Be it known that I, FRED WEIMAR, a citizen of the United States ofAmerica, residing at Chicago,in the county of Stephenson and State ofIllinois, haveinvented certain new and useful Improvements in Calipers,of which the following is a specification.

My invention relates to certain improve-- ments in calipers, designed torender more :0 easy and certain the use of the same, so that a novicemay be able to obtain as accurate or even more accurate results than arepossible after years of practice with the common form of caliper. Thedifficulty which it is designed to overcome is due to the elasticity ofthe arms of the ordinary calipers,by reason of which accuratemeasurements, either with inside or outside calipers, are exceedinglydifficult.

It is the purpose of my invention to provide a device which may beapplied to one of the points of thecalipers to form an extension thereofand to be movable relatively thereto, so as to move backward from thedirection of engagement of the point-s with such ease as to avoid anyspringing of the caliper-arms themselves. It is also my purpose topreferably construct said device so'that the extent of its movementrelative to the arm of which it forms the extension may be read from agraduated device provided for the purpose of registering the amount ofsuch movement.

To such end the invention consists in certain novel characteristics,which will be described in connection with the preferred construction,and the essential features of which will be defined in the claims.

In the drawings, Figure 1 is a view of a pair of ordinary calipersprovided with my invention in its preferred form and shown in the act ofgaging the diameter of a cylindrical. body. Fig. 2 is a perspective ofthe device which is applied to one of the caliper-arms; and Fig. 3 is asection of Fig. 2, showing the method of its application thereto.

5 Referring to the drawings, A represents a pair of ordinary calipershaving the arms a a,

' the calipers here shown being of the ordinary form known as outsidecalipers.

B B, Fig. 2, are apair of plates curved pref- I erably to accommodatethem somewhat to the shape of the caliper-point and having lateralextensions 1) b, spaced apart by astrntb which is secured to the twoplates by means of solder or otherwise or, indeed, may be made integraltherewith. One of these extensions is graduated,as seen at b ,thepurpose of which will be described below. Aclamping-screw C providesmeans for clamping the two plates tightly to the opposite sides'of thecaliperpoint, and a second strut or bridge I), Fig. 3, provides astopfor the end of said point. Between the plates and immediately beyondthis bridge is apivoted lever D, having the point (1 extending outbeyond the caliper-point anda finger d extending upon the opposite sideof the pivot to the graduation 6 The pivot is shown at E,and the levershould work thereon with slight frictional resistance, so as to tend toalways remain in any given position and yet to move therefrom with suchfreedom as to avoid springing of the arms of the cal-iers.

p In using the invention the finger d is crowded back against the plateB, as seen in Fig. 1, thereby extending the point d to its greatestdistancein the direction of the point of the other caliper-arm, and thecaliper is applied to the article to be gaged, as is seen in Fig. 1,placing the same between the caliper-arms in the ordinary manner anddrawing the caliper backward to pass said article between the pointsthereof. Care should be taken to keep the exposed caliper-point againstthe object to be gaged, and as the latter passes between the points thelever D will be moved upon its pivot sufficiently to permit the articleto pass between it and the opposite point. The graduations afford meansfor readily noting the amount of movement of the lever, and a similarapplication of the caliper to a model or sample which is to beduplicated ,will determine with great accuracy whether the two are ofexactly the same diameter.

I recognize the possibility of great variation in form without departingfrom the invention, 5 and I therefore do not limit myself to thespecific construction herein set forth. I

I claim as new and desire to secure by Letters Patent 1. Thecombination, in a pair of calipers, 100

and with one of the contact-points thereof, graduation, and movable overthe same to of an extension supported thereon freely and indicate theextent of independent movement independently movable by the applicationof of the lever, said lever moving with sufficient force, but otherwisetending to remain in pofrictional resistance to remain in any of its 5sition with respect thereto, said extension bepositions until force isapplied to move it 20 ing provided with means for accuratelydetherefrom, substantially as described.

termining the extent of its movement inde- In Witness whereof I havehereunto set my pendent of the caliper-point; substantially as hand, atChicago, in the county of Cool: and

described. l State of Illinois, this 13th day of April, A. D. to 2. Thecombination with a caliper-point, of 1901.

an extension secured thereto, having a radu- ,1

ated portion, and a pivoted lever w vith a FRED VVLIMAR shorter armprojecting beyond the caliperi Witnesses:

point and adapted to act as a continuation CHAs. i). SHERVEY,

15 thereof, and a longer arm extending to said r). BLISS.

